|Scientific Name:||Myliobatis aquila|
|Species Authority:||(Linnaeus, 1758)|
Raja aquila Linnaeus, 1758
|Taxonomic Notes:||It is unclear whether this, or a similar, species occurs along the east and west African coasts and Mediterranean Sea. A systematic review of this species is need in these areas.|
|Red List Category & Criteria:||Data Deficient ver 3.1|
|Assessor/s:||Holtzhausen, J.A., Ebert, D.A., Serena, F. & Mancusi, C.|
|Reviewer/s:||Cavanagh, R.D., Valenti, S.V. & Pollard, D. (Shark Red List Authority)|
This semi-pelagic ray occurs from the North Sea to South Africa in the eastern Atlantic, including the Mediterranean Sea, and also off Kenya and South Africa in the Western Indian Ocean. The Common Eagle Ray (Myliobatis aquila) appears to prefer inshore waters (<50 m), although it has been reported from depths of up to 537 m off southern Africa. This species often swims in groups close to the bottom. Populations in Europe may differ from populations elsewhere and a systematic review of the species in these areas is required. Common Eagle Ray appears to be less common in the Mediterranean Sea and possibly the eastern Atlantic. Time series data from demersal fishery landings and demersal trawl surveys show that this species declined in the Gulf of Lions, northwestern Mediterranean Sea, in the late1970s. It was recorded in low numbers during northern Mediterranean-wide trawl surveys from 1994–1999, and is still sometimes observed on fish markets. Few data are currently available to assess trends in other areas of the Mediterranean Sea, but given that fishing pressure is high throughout this species’ bathymetric range there, declines are also likely to have occurred elsewhere. This species is assessed as Near Threatened in the Mediterranean Sea. Further investigation of catch trends in the southern Mediterranean is required and with further information this species may prove to meet the criteria for Vulnerable A2bd+A3bd. No data are currently available from the eastern central Atlantic, but this species is presumably taken in coastal artisanal fisheries along the coast of western Africa and investigation of the species’ status in this area is a priority. Off southern Africa, it only rarely taken as bycatch and is not subjected to great fishing mortality. Available time series data on catches of this species from 1981–2001 showed no trend, and the species is assessed as Least Concern in southern Africa. The lack of data on catches and population trends throughout the species’ range and uncertain taxonomic status of populations in Europe and southern Africa precludes a global assessment beyond Data Deficient at present. This assessment should be revisited when these issues are better resolved.
|Range Description:||Eastern Atlantic Ocean: from Ireland and the North Sea, south to South Africa, including Madeira, Morocco and the Azores, and along the eastern African coast to Angola, Namibia and South Africa. It ranges throughout the Mediterranean Sea, but is absent from the Black Sea (Serena 2005). It is also found off Kenya and South Africa in the western Indian Ocean.
Populations in Europe may be regionally different compared to elsewhere.
Native:Albania; Algeria; Angola (Angola); Benin; Cameroon; Cape Verde; Congo; Congo, The Democratic Republic of the; Côte d'Ivoire; Croatia; Cyprus; Egypt; Equatorial Guinea; France; Gabon; Gambia; Ghana; Greece; Guinea; Guinea-Bissau; Ireland; Israel; Italy; Jordan; Kenya; Liberia; Libya; Madagascar; Mauritania; Montenegro; Morocco; Namibia; Nigeria; Senegal; Sierra Leone; Slovenia; South Africa; Spain; Syrian Arab Republic; Togo; Tunisia; Turkey; United Kingdom; Western Sahara
|FAO Marine Fishing Areas:||
Atlantic – eastern central; Atlantic – northeast; Atlantic – southeast; Mediterranean and Black Sea
|Range Map:||Click here to open the map viewer and explore range.|
This species is common in the southern part of its range (southern Africa) (J.A. Holtzhausen and D.A. Ebert pers. obs.), however it appears to be less common in European waters. In South Africa, data on catches of this species in the Natal Sharks Board beach nets showed no trend from 1981–2001 (Young 2001).
Aldebert (1997) examined long-term changes in groundfish diversity in the Gulf of Lions, France, northwestern Mediterranean Sea. This study analysed trends in both commercial landings in the demersal fishery (mostly trawl) from 1970–1995 and data from bottom trawl survey from 1957–1995. Analysis of commercial landings showed a clear decrease this species during the study period, and after the late 1970s it remained absent (Aldebert 1997). Results obtained from experimental surveys confirmed that decreasing trends were most likely related to the continuous increasing fishing intensity, resulting in a general decline in stocks and not changing patterns of effort in the fishery.
This species occurred in low numbers in MEDITS surveys conducted from 1994–1999 at depths of 10–800 m. It was captured in 37 of 6,336 scientific survey hauls conducted throughout the northern Mediterranean during this period (Baino et al. 2001).
No data are currently available on catch trends elsewhere.
|Habitat and Ecology:||
This semipelagic ray is found inshore and offshore, it appears primarily to occur in inshore, coastal areas (<50 m), readily entering shallow lagoons and estuaries, although it has been reported from depths of up to 537 m in some areas (Whitehead et al. 1984). In the Mediterranean Sea it is reported to occur on sandy and muddy substrates, to 200 m depth (Notarbartolo and Bianchi 1998, Serena 2005). They can often be found in groups swimming close to the bottom. Reproduction is ovoviviparous (Whitehead et al. 1984).
Life-history parameters appear to vary regionally. In the Mediterranean Sea, M. Aquila reaches a maximum size of 150 cm disc width (DW) and 260 cm total length (TL) (Notarbartolo and Bianchi 1998, Fischer et al. 1987). Females mature at 60 cm DW and males at 40 cm DW (Fischer et al. 1987, Serena 2005). Females give birth to 3–7 pups per litter, after a gestation period of 6–8 months (Fischer et al. 1987, Whitehead et al. 1984, Serena 2005). Reproduction takes place between September and February (Notarbartolo and Bianchi 1998).
Off southern Africa, this species reaches a maximum size of 79.1 cm DW, with males maturing at 31.8 cm DW and females at 42.5 cm DW.
It feeds on invertebrates such as crabs, molecrabs and bivalves, and on small bony fishes.
This species is susceptible to a variety of fishing gears, including bottom trawls, purse seines, gillnets and line-gear. It is taken as bycatch in various fisheries, including both commercial and artisanal, throughout its range in the Mediterranean Sea and presumably in the tropical Atlantic. There is no information on the catch of this species in targeted fisheries, although it is almost certainly taken in artisanal fisheries in the tropical Atlantic. This species’ schooling behavior means that large numbers could be fished out in one haul, and fishermen are known to target aggregations of rays off western Africa.
Fisheries have increased in both effort and capacity in the Mediterranean Sea during recent decades (Aldebert 1997). The continental shelf and upper slope of the Mediterranean Sea are subject to high levels of exploitation, down to a depth of 800 m (i.e., throughout much of this species’ bathymetric range) (Massuti and Moranta 2003). Data from trawl surveys and fisheries landings suggest that this species declined in the northern Mediterranean in the late 1970s and was absent from the catches until 1995.
In southern Africa is it only rarely taken as bycatch with bottom trawls, purse seines, longlines, or by shore anglers, and is not subjected to great fishing mortality. About 65–70% of M. aquila captured in Natal Sharks Board beach protection nets are released alive, with presumed high survival (S. Dudley pers. comm. 2005).
Habitat degradation in inshore areas from coastal development and pollution may also affect this species’ in inshore habitat.
|Conservation Actions:||None in place.|
|Citation:||Holtzhausen, J.A., Ebert, D.A., Serena, F. & Mancusi, C. 2009. Myliobatis aquila. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 18 May 2013.|
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